Throttle valve device



" ocnzo, 1936.1 JQMCCUNE 2,058,028

THRAOTTL VALVE DEVICE Filed Maron .15, 1935 INVENTOR A TTORN PatentedOct. 20, 1936 UNITED 4STATES PATlez-NTA OFFICE:Y

THROTTLE-VALVE DEVICE V Joseph C. McCune, dgewoodga., 'vasjsignor to TheWestinghouse Air Brake Company, Wilmerdng, Pa., a corporation ofl`Pennsylvania Application March 15, 1933,Serial No. 660,786

6 claims; (c1. 13d- 139) This invention relates to throttlevalve devicesand particularly to valve devices for controlling the delivery of steamdriven air compressors such as are employed on railway locomotives.

Locomotives equipped for supplying superheated steam to the drivingcylinders and appurtenant apparatus of the locomotive are usuallyequipped with means for generating superheated steam as required and forregulating the temperf 10` ature of the steam delivered to the cylindersand appurtenant apparatus, so that when superheated steam is notrequired, saturated steam may be supplied to the driving cylinders, aswhen descending long grades where little or no power is required tomaintain the speed of the train.

Because of the greater efciency of the superheated steam, the usualsteam driven compressor is driven with greater rapidity when thesuperheated steam is supplied thereto than when op- 201 erated bysaturated steam at like pressure.

Since the increase in speed of operation of theV compressor isunnecessary, the operation with superheated steam is wasteful unless thesupply of superheated steam is throttled to maintain the desirable speedof operation. It is, therefore, advantageous to reduce the delivery ofsuper-l heated steam to the engine of the compressor in accordance withthe increase in temperature of the steam delivered, so that thecompressor is 30. operated substantially at a constant speed regardlessof whether saturated steam or superheated steam is supplied to theengine of the compressor.

An object of the invention is to provide a throttle valve devicev for asteam driven `air compressor and having means for automaticallyregulating the delivery of steam to the engine for operating thecompressor so that the compressor will be driven at a uniform speedregardless ofr whether the engine is being supplied with-saturated steamor with superheated dry steam.

A further object of the invention isto'provide a throttle valve devicehaving the above noted characteristics wherein a movable valve serves to45 control the passage of steam through a by-passl passage, and whichvalve is operated by a thermally responsive bi-metal element and movedto closed position for closing the by-pass passage when superheatedsteam is being supplied tothe` 50, engine of the compressor.

A further-object of the invention is to providea throttle valve devicefor the purpose described, that may be placed in the steam conduitleading from the superheater of the locomotive to the 55l engine of:the. compressor `and which isprovided .a

withia permanently openpassage having a flow area of sufficient size todeliver the proper amount of superheated steam to the engine of thecompressor formaintaining a predetermined` or desired operating speedthereof and which is 5'*- also provided with a by-pass and a normallyopen control valve therefor thatA is open when saturated steam issupplied tothe engine and whichV is automatically moved toward closedposition as the temperature of the steam is increased, as '10" whensuperheated steam is delivered to the engine of the compressor, so thatthe quantity of steam `delivered to the engine is reduced when thatsteam is superheated.

.These and otherobjects of the invention that 15 will be madev apparentthroughout the further description thereof are attained by means of theapparatus hereinafter described and illustrated in the 'accompanyingdrawing; wherein,

Fig. 1 is anelevational view of a steam driven 20 fluid icomprssor andtheimproved throttle valve device associated therewith;

'Fig.f2 Vis -a longitudinal section through the throttle valve. deviceshown in Fig. 1, the throttle Valve A`device being, shown in the coldcondition thereof, thatis without steam flowing therethrough; f

Fig. 3 is a transverse section through the throttle Valve device takenon the line 3-3 of Fig-...2: and Y c Fig. 4 is a fragmental sectionalview taken on the line ll-llof v Fig. 3 showing the laminatedconstruction of vthe loi-metal valve operating d evie.'v 35 Referringtothe drawing, a standard steam driven air compressor `is. disclosedcomprising a steam driven engine Il, a `huid compressor I2 that isdriven by the; operating piston rod i3, and the improved throttlevvalve, device I4 that is 40 connected-inthe steamV supply pipe I5 whichleads fromthesuperheater of the locomotive, not shown, to the engine Il.

The .throttle valve device comprises a casing lll havingfan inletchamber IB and an outlet y chamber. l'l. separated by a partition wallI8 havingpaa permanently open steam passage i9 establishingcommunication between the inlet and outlet .chambers tti-andv I1respectively. The flow area of the passage [Sl-may be altered as desiredby inserting a screwplug 2| having an orifice 22, theflowarea oi whichis of suiiicient size to permit the passage-oi` suztlicient steam to theengine of-'the compressor tof-maintain the desired and most'advantageous-1 speedof V operation when 552 superheated steam issupplied to the engine from the locomotive superheater, not shown.

Since a greater quantity, by weight, of saturated steam must be suppliedto the engine of the compressor to maintain a given speed of operationthan when superheated steam is supplied thereto, it is necessary toprovide an additional passage or by-pass for the flow of steam from theinlet chamber to the outlet chamber, so that suicient saturated steammay be supplied to the engine of the compressor through the passage |9and the by-pass passage to maintain the desired operating speed of thecompressor.

The by-pass passage comprises a chamber 23 in a bushing 20 and which isopen to the chamber I6 through four passages 30, and passages 24 and 25leading from the chamber 23 and opening into the chamber |1, the passage24 opening into a passage 26 in the casing of the throttle valve devicewhich leads from the chamber I1. The bushing 20 is centered in thechamber I6 so that two relatively large passages past the bushing fromthe inlet to the outlet side of chamber |6 are provided, as shown inFigure 3. A valve 21 within the chamber 23 and a valve 28 within thechamber |1 and connected by a uted stem 29 having a cylindrical portion38, serve to close the passages 24 and 25 respectively when the valvesare moved axially upwardly. The valves are pres- `sure balanced and areoperated by means of a laminated bi-metal thermal element 3| that ismounted in a supporting member 32 that is secured within the chamber |1of the casing. The valve 28 is provided with a flat extension 33 havinga slot 34 in which the central portion of the bi-metal element 3| isdisposed in such manner that when the bi-metal element 3| is bowedupwardly, as when the temperature thereof is increased, the valves 21and 28 are moved toward closed position.

The rate of flow of steam through the by-pass passages 24 and' 25 issubstantially constant, as the valves 21 and 28 are moved upwardly,until the valves reach a certain intermediate position, beyond whichfurther movement thereof eiects a restriction or reduction in the rateof ilow of steam through the passages 24 and 25.

The expansion characteristics of the bi-metal thermal element 3| aresuch that the valves 21 and 28 do not reach the certain intermediateposition as long as saturated steam is supplied through the throttlevalve device, assuming that the saturated steam is below a certainpressure, the valves 21 and 28 being raised beyond the certainintermediate position only when superheated steam, at or above itsminimum temperature for the same pressure as that of the saturatedsteam, which minimum temperature is higher than the temperature of thesaturated steam, is supplied through the throttle valve device.

'I'he degree of reduction in the rate of ow of superheated steam throughthe by-pass passages 24 and 25 is substantially in direct proportion tothe temperature of the superheated steam, and thus the rate of flow ofsuperheated steam through the passages 24 andl 25 is reduced in inverserelation to the increase in the temperature of the superheated steamuntil a predetermined high temperature is attained at which the thermalelement 3| has raised the valves 21 and 28 sufficiently to entirelyclose the passages 24 ,and 25 and completely cut oi the flow ofsuperheated steam through the by-pass passages.

Thus, over a considerable range of temperatures between the minimumtemperature and the predetermined high temperature of superheated steam,above mentioned, there is a regulation of the ow of superheated steamthrough the bypass passages 24 and 25, so that for a given load on thedriving engine of the compressor there is substantially no change in thespeed of operation of the driving engine with changes in the temperatureof the superheated steam. Furthermore, since regulation of the flow ofsuperheated steam begins substantially at the minimum temperaturethereof, there is substantially no change in the speed of operation ofthe driving engine of the compressor for a given load thereon, whensuperheated steam is supplied through the throttle valve device ascompared to that when saturated steam is supplied through the throttlevalve device.

If the temperature of the superheated steam increases above thepredetermined high temperature there is, of course, no regulation of theow of superheated steam, but the range of temperatures 4of superheatedsteam over which the throttle valve device is effective to regulate theow of superheated steam is calculated to take care of the usualoperating temperatures of superheated steam employed.

The casing of the throttle valve device is provided with a cover 31 forclosing the opening 35 in the chamber |1, through which opening thevalves 21 and 28, stem 29 and thermal element 3| are inserted duringassembly of the valve device. Suitable union pipe connections 36 arealso provided for eiecting steam-tight joints between the casing and thepipe.

In operation, assuming the compressor engine and the steam supply pipeto be cold, and' that because of the cold condition of the apparatus,saturated steam is initially supplied to the pipe l5 and to the throttlevalve device i4 and the compressor engine the valves 21 and 28 are inthe open position and saturated steam is supplied to the engine of thecompressor through passage I9 and through the by-pass passages 24 andl25.

As the bi-metal element 3| bows upwardly, the valves 21 and 28 areraised to their intermediate position in the manner previouslydescribed, the permanently open passage |9 andv the open bypass passagespermitting the proper amount of saturated steam to ilow to the enginefor op-erating the engine at the desired speed.

When superheated steam is supplied to the pipe I5 and to the throttlevalve device, the bi-metal element 3| is heated above the minimumtemperature of superheated steam for the pressure employed and is causedto bow further upwardly to effect further upward movement of the valves21 and 28, thereby reducing the flow area of the bypass passages 24 and25, in the manner above described, and correspondingly reducing thequantity of steam supplied to the engine so that the speed of operationof the compressor is maintained substantially constant for a given loadthereon.

If the temperature of the superheated steam be reduced to that ofsaturated steam, as when the locomotive is descending a long grade andsaturated steam is then supplied to the pipe |5 and the engine thetemperature of the bi-metal element 3| will be correspondingly reduced,and as it assumes its normal position, it moves the valves 21 and 28toward open position, thereby increasing the iiow area of the by-passpassage and permitting a greater quantity of saturated steam to ow tothe compressor engines and maintain proper operating speed thereof. Itwill be. understood that the expansion characteristics of. the bi-metalelement 3| may be such that as the temperature of the steam variesbetween that of saturated steam and superheated dry steam, the quantityf steam supplied to the compressor engine is regulated to maintain aconstant operating speed.

While the device is disclosed as applied to the steam engine of a fluidcompressor, it is obvious that the throttle valve device may be used forregulating the delivery of steam to other steam driven apparatus formaintaining a constant speed of operation thereof regardless ofvariations in the temperature of the steam delivered thereto.

While but one embodiment of. the invention is disclosed, it is .obviousthat additions and omissions and other changes may be made in thestructure without departing from the spirit of the invention.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A temperature regulated steam throttle valve device comprising acasing having an inlet chamber and an outlet chamber, a valve portionmounted for removal through the bottom of said casing between said twochambers and having two passages therethrough for establishingcommunication between said chambers through which steam may flow, one ofsaid passages being permanently open and adapted to permit a relativelylarge flow of. steam to be maintained therethrough, a valve for closingthe other passage, and a thermal responsive element for actuating saidvalve into closing position only upon a predetermined temperature of thesteam flowing through said chambers.

2. A temperature regulated steam throttle valve device comprising acasing having an inlet chamber and an outlet chamber, a valve portionmounted for removal through the bottom of. said casing betwn saidchambers and enclosing a valve chamber having a passage communicatingwith said inlet chamber, a constantly open passage for effectingcommunication between said valve chamber and said outlet chamber, andbypass passages for effecting communication from said valve chamber tosaid outlet chamber, a valve for closing the by-pass passages, and athermal responsive element for actuating said valve into closingposition upon a predetermined increase in temperature of the steamflowing through said chambers.

3. A temperature regulated steam throttle valve device comprising acasing having an inlet chamber and an outlet chamber, a valve portionenclosing a valve chamber removably mounted in said casing between saidinlet and outlet chambers providing permanently open dividing passagesbetween said outlet and said inlet chambers about said valve portion, apassage for effecting communication between said valve chamber and saidoutlet chamber, and a by-pass passage for effecting communication fromsaid valve chamber to said outlet chamber, a valve for closing theby-pass passage, and a thermal responsive element for actuating saidvalve into closing position upon a predetermined temperature of thesteam flowing through said chambers.

4. A temperature regulated steam throttle valve device comprising acasing having an inlet chamber and an outlet chamber, a valve portionremovably mounted in said casing between said inlet and outlet chambersand enclosing a valve chamber, passages for effecting constant opencommunication between said inlet and outlet chambers, a passage foreffecting constant communication between said inlet chamber and saidvalve chamber, and by-pass passages leading in the opposite directionsfrom said valve chamber for effecting communication with said outletchamber, pressure balanced valves for closing said by-pass passages, anda thermal responsive element in said outlet chamber for actuating saidvalves into closing position upon a predetermined increase in thetemperature of the steam flowing` through said chambers.

5. A temperature regulating steam throttle valve device comprising acasing having an inlet chamber and an outlet chamber separated by apartition wall, a valve portion extending through said wall andcomprising a bushing enclosing a central chamber and having a boretherethrough forming by-pass passages leading from said central chamberto said outlet chamber, pressure balanced valves for closing saidby-pass passages having a common stem positioned in said bore, and athermal responsive element in said casing for actuating said valve intoclosing position upon a predetermined temperature of the steam owingthrough said chamber.

6. A temperature regulated steam throttling device through whichsaturated steam at a given pressure and corresponding temperature andsuperheated steam at substantially the same pressure but above apredetermined higher temperature than that of the saturated steam issupplied at different times, comprising a casing having an inlet chamberand .outlet chamber, a valve portion enclosing a valve chamber removablymounted in said casing between said inlet and outlet chambers providingpermanently open divided passages between said outlet and inlet chambersabout said valve portion, a passage for effecting communication betweensaid valve chamber and said outlet chamber, and a by-pass passage foreffecting communication from said valve chamber to said .outlet chamber,a valve for closing said by-pass passage, and a thermal responsiveelement subject to the heat of the steam flowing through the throttlingdevice for actuating said valve into closing position upon apredetermined temperature of steam iiowing therethrough, said thermalresponsive element being adjusted to operate the said valve device toreduce the flow of only superheated steam in relation to the temperatureof the superheated steam above the predetermined temperature, saidthermal responsive device being ineffective to so operate the valvedevice and to reduce the flow of saturated steam.

JOSEPH C. MCCUNE.

